Eight Years of SOHO - Some Highlights
Publication date: 01 Oct 2004
Authors: Fleck, B.
Journal: Solar Magnetic Phenomena, Proc. Kanzelhoehe Summerschool and Workshop
Copyright: SpringerSince its launch on 2 December 1995, the joint ESA/NASA SOHO mission has provided a wealth of information about the Sun, from its interior, through the hot and dynamic atmosphere, to the solar wind and its interaction with the interstellar medium. Analysis of the helioseismology data from SOHO has provided the first images of structures and flows below the Sun's surface and has shed new light on a number of structural and dynamic phenomena in the solar interior, such as the absence of differential rotation in the radiative zone, subsurface zonal and meridional flows, and sub-convection-zone mixing. Evidence for an upward transfer of magnetic energy from the Sun's surface toward the corona has been established. The ultraviolet imagers and spectrometers have revealed an extremely dynamic solar atmosphere where plasma flows play an important role. Electrons in coronal holes were found to be relatively ``cool', whereas heavy ions are extremely hot and have highly anisotropic velocity distributions. The source regions for the high speed solar wind have been identified and the acceleration profiles of both the slow and fast solar wind have been measured. SOHO has also revolutionized our space weather forecasting capabilities by providing a continuous stream of images of the dynamic atmosphere, extended corona, and activity on the far side of the Sun. At the same time, SOHO's easily accessible images and movies have captured the imagination of the science community and the general public alike. This article summarizes some of the key findings from 8 years of SOHO.